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This prevented Prometheus metrics from being gathered from the URL. Signed-off-by: Alex Ellis (VMware) <alexellis2@gmail.com>
247 lines
7.0 KiB
Go
247 lines
7.0 KiB
Go
package handlers
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import (
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"context"
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"fmt"
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"io"
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"log"
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"net/http"
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"regexp"
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"strconv"
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"strings"
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"time"
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"github.com/openfaas/faas/gateway/metrics"
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"github.com/openfaas/faas/gateway/types"
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"github.com/prometheus/client_golang/prometheus"
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)
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// functionMatcher parses out the service name (group 1) and rest of path (group 2).
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var functionMatcher = regexp.MustCompile("^/?(?:async-)?function/([^/?]+)([^?]*)")
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// Indicies and meta-data for functionMatcher regex parts
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const (
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hasPathCount = 3
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routeIndex = 0 // routeIndex corresponds to /function/ or /async-function/
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nameIndex = 1 // nameIndex is the function name
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pathIndex = 2 // pathIndex is the path i.e. /employee/:id/
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)
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// HTTPNotifier notify about HTTP request/response
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type HTTPNotifier interface {
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Notify(method string, URL string, originalURL string, statusCode int, duration time.Duration)
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}
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// BaseURLResolver URL resolver for upstream requests
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type BaseURLResolver interface {
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Resolve(r *http.Request) string
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}
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// URLPathTransformer Transform the incoming URL path for upstream requests
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type URLPathTransformer interface {
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Transform(r *http.Request) string
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}
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// MakeForwardingProxyHandler create a handler which forwards HTTP requests
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func MakeForwardingProxyHandler(proxy *types.HTTPClientReverseProxy, notifiers []HTTPNotifier, baseURLResolver BaseURLResolver, urlPathTransformer URLPathTransformer) http.HandlerFunc {
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return func(w http.ResponseWriter, r *http.Request) {
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baseURL := baseURLResolver.Resolve(r)
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originalURL := r.URL.String()
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requestURL := urlPathTransformer.Transform(r)
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start := time.Now()
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statusCode, err := forwardRequest(w, r, proxy.Client, baseURL, requestURL, proxy.Timeout)
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seconds := time.Since(start)
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if err != nil {
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log.Printf("error with upstream request to: %s, %s\n", requestURL, err.Error())
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}
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for _, notifier := range notifiers {
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notifier.Notify(r.Method, requestURL, originalURL, statusCode, seconds)
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}
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}
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}
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func buildUpstreamRequest(r *http.Request, baseURL string, requestURL string) *http.Request {
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url := baseURL + requestURL
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if len(r.URL.RawQuery) > 0 {
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url = fmt.Sprintf("%s?%s", url, r.URL.RawQuery)
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}
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upstreamReq, _ := http.NewRequest(r.Method, url, nil)
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if len(r.Host) > 0 {
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upstreamReq.Host = r.Host
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}
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copyHeaders(upstreamReq.Header, &r.Header)
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upstreamReq.Header["X-Forwarded-For"] = []string{r.RemoteAddr}
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if r.Body != nil {
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upstreamReq.Body = r.Body
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}
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return upstreamReq
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}
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func forwardRequest(w http.ResponseWriter, r *http.Request, proxyClient *http.Client, baseURL string, requestURL string, timeout time.Duration) (int, error) {
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upstreamReq := buildUpstreamRequest(r, baseURL, requestURL)
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if upstreamReq.Body != nil {
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defer upstreamReq.Body.Close()
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}
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ctx, cancel := context.WithTimeout(context.Background(), timeout)
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defer cancel()
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res, resErr := proxyClient.Do(upstreamReq.WithContext(ctx))
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if resErr != nil {
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badStatus := http.StatusBadGateway
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w.WriteHeader(badStatus)
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return badStatus, resErr
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}
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if res.Body != nil {
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defer res.Body.Close()
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}
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copyHeaders(w.Header(), &res.Header)
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// Write status code
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w.WriteHeader(res.StatusCode)
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if res.Body != nil {
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// Copy the body over
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io.CopyBuffer(w, res.Body, nil)
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}
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return res.StatusCode, nil
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}
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func copyHeaders(destination http.Header, source *http.Header) {
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for k, v := range *source {
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vClone := make([]string, len(v))
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copy(vClone, v)
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(destination)[k] = vClone
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}
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}
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// PrometheusFunctionNotifier records metrics to Prometheus
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type PrometheusFunctionNotifier struct {
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Metrics *metrics.MetricOptions
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}
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// Notify records metrics in Prometheus
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func (p PrometheusFunctionNotifier) Notify(method string, URL string, originalURL string, statusCode int, duration time.Duration) {
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seconds := duration.Seconds()
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serviceName := getServiceName(originalURL)
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p.Metrics.GatewayFunctionsHistogram.
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WithLabelValues(serviceName).
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Observe(seconds)
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code := strconv.Itoa(statusCode)
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p.Metrics.GatewayFunctionInvocation.
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With(prometheus.Labels{"function_name": serviceName, "code": code}).
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Inc()
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}
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func getServiceName(urlValue string) string {
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var serviceName string
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forward := "/function/"
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if strings.HasPrefix(urlValue, forward) {
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// With a path like `/function/xyz/rest/of/path?q=a`, the service
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// name we wish to locate is just the `xyz` portion. With a postive
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// match on the regex below, it will return a three-element slice.
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// The item at index `0` is the same as `urlValue`, at `1`
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// will be the service name we need, and at `2` the rest of the path.
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matcher := functionMatcher.Copy()
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matches := matcher.FindStringSubmatch(urlValue)
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if len(matches) == hasPathCount {
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serviceName = matches[nameIndex]
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}
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}
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return strings.Trim(serviceName, "/")
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}
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// LoggingNotifier notifies a log about a request
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type LoggingNotifier struct {
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}
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// Notify a log about a request
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func (LoggingNotifier) Notify(method string, URL string, originalURL string, statusCode int, duration time.Duration) {
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log.Printf("Forwarded [%s] to %s - [%d] - %f seconds", method, originalURL, statusCode, duration.Seconds())
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}
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// SingleHostBaseURLResolver resolves URLs against a single BaseURL
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type SingleHostBaseURLResolver struct {
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BaseURL string
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}
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// Resolve the base URL for a request
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func (s SingleHostBaseURLResolver) Resolve(r *http.Request) string {
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baseURL := s.BaseURL
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if strings.HasSuffix(baseURL, "/") {
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baseURL = baseURL[0 : len(baseURL)-1]
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}
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return baseURL
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}
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// FunctionAsHostBaseURLResolver resolves URLs using a function from the URL as a host
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type FunctionAsHostBaseURLResolver struct {
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FunctionSuffix string
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}
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// Resolve the base URL for a request
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func (f FunctionAsHostBaseURLResolver) Resolve(r *http.Request) string {
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svcName := getServiceName(r.URL.Path)
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const watchdogPort = 8080
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var suffix string
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if len(f.FunctionSuffix) > 0 {
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suffix = "." + f.FunctionSuffix
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}
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return fmt.Sprintf("http://%s%s:%d", svcName, suffix, watchdogPort)
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}
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// TransparentURLPathTransformer passes the requested URL path through untouched.
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type TransparentURLPathTransformer struct {
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}
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// Transform returns the URL path unchanged.
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func (f TransparentURLPathTransformer) Transform(r *http.Request) string {
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return r.URL.Path
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}
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// FunctionPrefixTrimmingURLPathTransformer removes the "/function/servicename/" prefix from the URL path.
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type FunctionPrefixTrimmingURLPathTransformer struct {
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}
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// Transform removes the "/function/servicename/" prefix from the URL path.
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func (f FunctionPrefixTrimmingURLPathTransformer) Transform(r *http.Request) string {
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ret := r.URL.Path
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if ret != "" {
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// When forwarding to a function, since the `/function/xyz` portion
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// of a path like `/function/xyz/rest/of/path` is only used or needed
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// by the Gateway, we want to trim it down to `/rest/of/path` for the
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// upstream request. In the following regex, in the case of a match
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// the r.URL.Path will be at `0`, the function name at `1` and the
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// rest of the path (the part we are interested in) at `2`.
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matcher := functionMatcher.Copy()
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parts := matcher.FindStringSubmatch(ret)
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if len(parts) == hasPathCount {
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ret = parts[pathIndex]
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}
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}
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return ret
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}
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